| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a frequency synthesizer producing various local oscillation signals suppressed in sprious. <P>SOLUTION: In the frequency synthesizer 10A where the outputs of a plurality of oscillators 11, 12 are converted into signals having different phases through phase shifters 21, 22 for multiplication through a plurality of mixers 31, 32 and, further, the outputs of the mixers 31, 32 are subjected to frequency addion by an adder 40 to output a plurality of local oscillation signals 41, the local oscillation signal 41, taken out via a sampling switch 61, is multiplied by a signal obtained from a multiplier 64 for down conversion and the sprious of an objective frequency is extracted via a bandpass filter 62, then, a sprious strength signal 63-1 is detected by a sprious detecting unit 63 while the gain G of the mixer 31 is controlled by an amplitude error control unit 60 based on the sprious strength to suppress the sprious included in the local oscillation signal 41 to the minimum value thereof. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
